Running electrical wire through PVC pipe

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wrote:

Not in my neck o' the woods. Of course, the help in the big boxen wouldn't know a pull string if it fell on their heads. I really do get sick of knowing more about what they sell than the "associates" do.
Of course, the pricing is better at the supply house, so I just wait until Saturday AM and go there. Only downside is when, as happened recently, I got snowed in for two Saturdays in a row and thus my home projects ground to a halt...
nate
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wrote Re Re: Running electrical wire through PVC pipe:

"boxen"? Wow, that's soooo cool.
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wrote:

The local HD store here keeps a box of nylon twine at the overhead door exit. Used to bundle several pieces of trim or base molding together.
I've cut 30 - 50 feet before - free. It is there for the customer use.
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Isn't that polypropylene, the cheap stuff, often hard to knot? Nylon twine is much nicer and much more expensive.
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Polypropylene is Dupont Dacron, used for ropes on sailboats.
Jimmie
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re: "I've cut 30 - 50 feet before - free. It is there for the customer use."
Yes, it's there for customer use, but it's not "free".
It's cost is included in the store's overall operating costs and figured into the prices of the items on the shelf.
The string's not free, the coffee's not free, the non-help you get from many of the associates is not free. You're just not paying for it directly.
OK...I'll grant you the exception where you use the string and drink the coffee without *ever* buying anything from the store. In that case, it would be free.
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LouB wrote:

http://www.twacomm.com/catalog/model_430.htm?sid 0D34F253114CD7A86019CD4C848580
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wrote:

Ahl, yeah, I stared to say substantially more than 2 times as long as the pipe but couldn't quite remember why. Make the pull string that long and attach what is pulled in the middle, and there will still be some of it sticking out both ends when he is done pulling. He can run the same string back and forth, back and forth, pulling in either direction.
I don't think fishing line is going to be easy to attach anything to, especially compared to nylon string, but he may know more abou tfishing line than I do.
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wrote:

I know enough that fishing line is not used for pulling wire :-/
A local Casino paid (7.5M?) to have overhead lines and poles removed, so they could expand building. That underground cable was 5 inches wide (130,000 Volts?), along the Vegas Strip. What a pull that was, eh?
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PolyTwine is best. Doesn't deteriorate and is easy to find
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mm wrote:

I had good luck using a plumbing snake to go down from my attic to basement (2 story house) alongside the plumbing vent. By turning the snake back and forth when it stops going down, the end moved enough to find a clear path. If there is a path, you might be able to find it this way.
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Thanks to everbody for their responses.
I will be stopping by Home Despot today and pick up some pipe and see what kind of fitting I can use in this project.
Thanks, David
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PVC is commonly used for electric wire. Not a problem there. But you should run two separate conduits: one for data signals and one for 120/240V signals. The 120/240V lines are likely to cause interference in the data signals.
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Now here's a question. When they build houses why don't they put in a couple empty PVC conduits that run from basement to attic? It sure would make it a hell of a lot easier to run any cables later on. Especially in an age where people are adding all kinds of things, data, voice, AC, etc. Yet, I've never seen this done. I guess there could be some claim that it might let a fire spread easier, but I tend to doubt that's really much of an issue. Even if it were, there would be ways to still do it and seal it off.
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On Fri, 26 Feb 2010 07:20:08 -0800 (PST), snipped-for-privacy@optonline.net wrote:

Because it costs money. However, I did this in a few places in my mother's house as they were building it, forty years ago.

It's just a cost that few would every use. A builder isn't going to throw a couple of hundred dollars down the rat hole if he doesn't think people will pay even more. I'm quite sure that you could put it in the contract, though. About now, I'm sure you could get them to agree to let you do it at night. ;-)
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Hi David,

I just saw this posting, so I apologize if this has already been answered.
The general code restriction is not to run "romex" style cables in conduit. As you discovered, it is related to heat build-up from the cables in the confined space of the conduit.
I researched this myself a couple years ago, and code does allow exceptions to this when "short" conduit runs are used for physical protection only. For example, I ran romex in conduit at my in-laws house, from surface mounted outlets in the basement, up the wall to the floor structure. It's open at the top for heat to escape, has an anti-short bushing to prevent the conduit edge from cutting into the cable, and is strictly for physical protection. My inspector had no problems with it. But a two story run inside walls would probably be well outside that exception.

Technology changes quickly and it's not economical to install everything in hopes you might someday use it (or worse yet, guess wrong and spend a lot of money on something that's outdated in a few years).
I installed numerous boxes throughout our house with short conduit runs to the crawlspace (capping the ends to prevent drafts and keep out insects). I've replaced and reorganized various cables over the last five years and it's one of the best decisions I've ever made. My only regret is not installing larger conduit, as my needs have far outpaced what I ever thought I would need them for.
Heat concerns are not an issue for data cables (Cat5, Cat 6), Coax, phone, etc., so running conduit now for those is a great idea. Minimal cost and no harm done if you never use it. But you'll be very thankful if you do need it.
I do recommend installing the largest conduit you can afford that will fit in the wall (remember couplings are larger than the outside of the pipe itself). It's unlikely you would ever wish the conduit was smaller, but as you install more "stuff" in coming years, you'll appreciate the extra capacity.
As for power lines, I would run another conduit line (again, as big as will fit), with large junction boxes at each floor. You could run romex cables through the walls/ceilings, then transition to individual THHN wires in the conduit. Individual wires are made for running in conduit, and you can fit more in the same space than romex cables anyway.
Anthony
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HerHusband wrote:

The NEC explicitly allows Romex to be installed in PVC conduit (352.22). (There are similar permissions for other raceways.)
Heat is a potential problem for multiple cables. It is covered in Wayne's post.
--
bud--

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Bud,

Good catch. I missed that in my research a couple of years ago.
Still, the idea of installing conduit now for future work later, would seem to increase the chance that someone might try to fit more than one cable in the conduit.
One option that might prevent that is to install several smaller conduits, such that it would be difficult to fit more than one cable in each. If there were other routes available, it would reduce the temptation to force them in. Just a thought...
Anthony
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If the piece of conduit is just used as a sleeve, then you can put as many electrical cables in it as will fit without damage, as long as you pay attention to derating. You don't have to follow the conduit fill percentages, they apply only to conduit systems. As mentioned previously, for NM #14 and #12 cables, up to 9 current carrying conductors are OK without reducing the ampacity below the usual 15 and 20 amps, respectively.
Cheers, Wayne
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On Mon, 1 Mar 2010 20:04:29 +0000 (UTC), Wayne Whitney

You still have a fill limit on these short sections of pipe (60%) This adds up very fast because you are required to compute a cable as a circle with the diameter of it's widest dimension. Cable jackets are also not coated with the teflon jacket on THHN so they are hard to pull through, even one bend. If this isn't one straight shot, use wire lube. It is really better to run a complete raceway system and use THHN conductors for future runs. if you don't have a mixed use duct. ENT is a good, low cost method to provide future access for 1&2 family. Set a box at each end with a blank cover and you can do whatever you want with it later.
I just did a bathroom renovation in my house and every switch location was a home run to a central J box in the attic with 3/4" ENT so it will be trivial to change our mind later on what controls what. I did this on an addition and it has already paid for itself when we had a change.
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